Alec Baldwin has been vindicated in the "Rust" shooting case ... at least criminally, because the New Mexico prosecutors will drop the involuntary manslaughter case against him ... sources with direct knowledge tell TMZ.

We're told Baldwin has been informed the case against him is over. Attorneys Alex Spiro and Luke Nikas were expected to wage legal war in less than 2 weeks ... but the D.A. blinked in a big way.

Frankly, it makes a lot of sense. The D.A. has charged armorer Hannah Gutierrez-Reed with involuntary manslaughter, presumably because she's the expert, so it doesn't make a whole lot of sense why an actor would double-check her work.

Beyond that, although Baldwin is an executive producer on the movie, he's not the one making day-to-day decisions.

As you know, the accidental shooting took the life of cinematographer Halyna Hutchins.

The case against Baldwin will be dismissed without prejudice, meaning it could be filed in the future, but that seems to be little more than a face-saving move by the D.A.

Spiro and attorney Luke Nikas tell TMZ ... "We are pleased with the decision to dismiss the case against Alec Baldwin and encourage a proper investigation into the facts and circumstances of this tragic accident."